“We believe that the grave emotional instability indicated by Mr. Trump’s speech and actions makes him incapable of serving safely as president,” the letter reads.

Here’s how they explain their reasoning:

Mr. Trump’s speech and actions demonstrate an inability to tolerate views different from his own, leading to rage reactions. His words and behaviour suggest a profound inability to empathise. Individuals with these traits distort reality to suit their psychological state, attacking facts and those who convey them (journalists, scientists).

As the mental health experts acknowledge in the letter, it’s unusual for people in their position to take a position on the well-being of a public figure.

In 1973 ,the American Psychiatric Association (APA) banned members from speculating about the mental health of people they have not personally examined. Termed the “Goldwater Rule,” the APA adopted it in part to respond to some psychiatrists who had made some ill-advised statements about 1964 Republican presidential candidate Barry Goldwater.

Speaking to Business Insider for a separate story before the election, the personality psychologists Brent Roberts and Scott Lilienfield (neither of whom signed the New York Times letter) explained that in their field, secondary reports and descriptions of a person’s behaviour can be more valuable than any direct examination.

Other major psychological associations haven’t adopted their own versions of the Goldwater Rule, which covers psychiatrists.

The 37 experts who signed the letter write that psychiatry’s self-imposed silence was keeping them from sharing their expertise with journalists and members of Congress.

“We fear that too much is at stake to be silent any longer,” the letter reads.

Here’s the full list of psychiatrists, psychologists, and social workers who signed the letter: